fix: opt into fixed klog stderrthreshold behavior

[pierluigilenoci]

Problem

klog v2 defaults -logtostderr to true. When this flag is active, the -stderrthreshold flag is silently ignored — all log messages of every severity (INFO, WARNING, ERROR, FATAL) are unconditionally written to stderr.

This has been an open issue since 2020: kubernetes/klog#212

Fix

Bump klog from v2.130.1 to v2.140.0 in both staging modules (cli, code-generator) and opt into the fixed behavior in all 6 binaries:

• CLI tools: kubectl-kcp, kubectl-ws, kubectl-create-workspace
• Code generators: cluster-client-gen, cluster-informer-gen, cluster-lister-gen

The default stderrthreshold remains INFO so the observable behavior is unchanged.

References

• Upstream issue: stderrthreshold not honored when logtostderr is set kubernetes/klog#212
• Upstream fix: feat: fix stderrthreshold not honored when logtostderr is set (#212) + two new flags kubernetes/klog#432

Opt into fixed klog stderrthreshold behavior so that -stderrthreshold is honored even when -logtostderr=true.

[kcp-ci-bot]

Hi @pierluigilenoci. Thanks for your PR.

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[ntnn]

/ok-to-test

[ntnn]

/retest

That's odd. Might be the infra flaking.

[pierluigilenoci]

/retest

[pierluigilenoci]

/kind bug

[mjudeikis]

I would want to wait until the same version of klog lands here via rebase. Now this unaligns us from upstream
/hold

[pierluigilenoci]

@mjudeikis Thanks for the review and the context — that makes sense.

You're right that this PR bumps k8s.io/klog/v2 from v2.130.1 to v2.140.0 across all go.mod files, which would misalign from upstream until the next rebase. I understand wanting to avoid that.

Happy to keep this on hold until klog v2.140.0 (or newer) lands via upstream rebase. Once it does, the go.mod changes can be dropped and only the flag.Set calls would remain. No rush on our side — just ping me when the rebase happens and I'll rebase/update accordingly.

[pierluigilenoci]

Hi @mjudeikis — just a heads-up: klog v2.140.0 was released on March 6, 2026 (https://github.com/kubernetes/klog/releases/tag/v2.140.0), so the upstream dependency is now available.

I notice this PR also has a merge conflict that needs resolving. Would you like me to rebase and update the PR to align with the current main branch? Once rebased, the /hold could be removed since the klog version you were waiting for is now published.

Let me know how you'd like to proceed. Thank you!

[ntnn]

Hey, we are waiting to rebase our kubernetes fork on a kubernetes version, which will likely be released at the end of this month. When that is released we'll rebase our fork and kcp and then this pr can be rebased.

[pierluigilenoci]

CI fix pushed

Root cause: The virtual-workspace-framework staging module was missed when bumping k8s.io/klog/v2 from v2.130.1 to v2.140.0 across the monorepo. This caused three CI failures:

Check	Failure	Root cause
pull-kcp-lint	"no go files to analyze" in virtual-workspace-framework	stale go.mod caused module resolution issues
pull-kcp-verify	"go.mod and/or go.sum have been modified"	go mod tidy upgraded klog, creating uncommitted changes
pull-kcp-test-unit	"no Go files" / "go mod tidy needed"	same stale module issue

Fix: bumped k8s.io/klog/v2 to v2.140.0 in staging/src/github.com/kcp-dev/virtual-workspace-framework/go.mod and ran go mod tidy.

Regarding pull-kcp-test-e2e-multiple-runs: TestUseWorkspace failed with "the server could not find the requested resource (post workspaces.tenancy.kcp.io)" — this is an infra timing flake unrelated to the klog changes. The new push should re-trigger all checks.

[pierluigilenoci]

/retest

[pierluigilenoci]

Hi @ntnn @mjudeikis — I noticed the K8s fork bump landed on Apr 20 (24a0254), but klog remains at v2.130.1 in main. Since klog v2.140.0 didn't come through the rebase, would it make sense to lift the /hold and bump klog separately in this PR? Happy to rebase and adjust as needed. Thanks!

[ntnn]

Hi; that was just a bump of the old rebase to handle an unrelated ticket - namely making the upstream kubernetes garbage collector cluster-aware.
The rebase is actively being worked on and I linked this PR in the ticket for the rebase so it can be handled alongside it.

[kcp-ci-bot]

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[kcp-ci-bot]

@pierluigilenoci: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-kcp-verify	65b2a4c	link	true	/test pull-kcp-verify
pull-kcp-verify-codegen	65b2a4c	link	true	/test pull-kcp-verify-codegen

Full PR test history

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